[ItBites]

Most of the seat belt hardware uses 7/16 bolts. I use GR-8 fine thread, with nyloc GR-8 nuts. Must go thru a frame member or use back-up plates as has been mentioned. I use two weld tabs with the belt hardware in-between in order to correctly use the fastener in double-shear. Your harnesses should have similar mounting (double-shear). Shoulder harnesses should wrap around a harness bar - alternately, the double weld-tab, double shear method is less desirable, but acceptable. See seat belt manufacturer information on where to mount the anti-sub belt. It must be a specific distance from the fall line along your chest to the floor. Shoulder harnesses should NOT have an angle 'up' to the mounting or have a 'down' angle more than 10 deg.